1. Field of the Invention
This invention is related to a free piston internal combustion engine and starting methods.
2. Description of the Prior Art
Free piston internal combustion engines are simple in construction and can directly convert chemical energy into various kinds of power. However, it is very difficult to start such engines thereby making it unable to be widely utilized.
As the super charge effect of two-stroke engines is not eminent, it is proposed to adopt the well-known loop scavenging method and exhaust pipe tuning method to increase the efficiency. Tuning method is suitable for free piston engines, because its operating velocity is limited to smaller range thereby making it easier to accomplish the highest efficiency.
The previous hydraulic power output system utilizes adjustable pressure output system to adapt to different output pressure demands, which is a variable pressure output system. At present, it is replaced with full power stroke output, i.e. constant pressure output system. As the actual stroke of the engine according to the present invention is not all the same, there will be automatic compensation function in a certain range of the power output. That is to say, if the load is decreased, the stroke will become longer, but vice versa. This feature is helpful for operation and control.